Biodegradable diethanolamine derivative chelating agent and preparation process thereof

Abstract

The present invention relates to a new diethanolamine derivative chelating agent having a high water solubility, a good chelating property, and biological degradation. The said new chelating agent can be prepared from reaction of diethanolamine and cyclic anhydride compound using lewis acid as the catalyst. The said process is uncomplicated, and does not use a severe condition, and also reduces the use of harmful chemicals.

1 . A diethanolamine derivative chelating agent according to structure (I) 
       
         
           
           
               
               
           
         
         wherein: 
         R can be selected from groups with structure 
       
       
         
           
           
               
               
           
         
         when n is integer from 1 to 2, and y represents a hydrogen atom, an alkaline metal atom, or an alkaline earth metal atom. 
       
     
     
         2 . The diethanolamine derivative chelating agent according to  claim 1 , wherein the structure of the diethanolamine derivative chelating agent is 
       
         
           
           
               
               
           
         
         when y represents a hydrogen atom, an alkaline metal atom, or an alkaline earth metal atom. 
       
     
     
         3 . The diethanolamine derivative chelating agent according to  claim 1 , wherein the structure of the diethanolamine derivative chelating agent is 
       
         
           
           
               
               
           
         
         when n is integer from 1 to 2, and y represents a hydrogen atom, an alkaline metal atom, or an alkaline earth metal atom. 
       
     
     
         4 . The diethanolamine derivative chelating agent according to  claim 3 , wherein n is 1. 
     
     
         5 . The diethanolamine derivative chelating agent according to  claim 1 , wherein the structure of the diethanolamine derivative chelating agent is 
       
         
           
           
               
               
           
         
         when y represents a hydrogen atom, an alkaline metal atom, or an alkaline earth metal atom. 
       
     
     
         6 . A process for preparing the diethanolamine derivative chelating agent according to  claim 1 , wherein said process comprises the following steps:
 a) mixing diethanolamine and cyclic anhydride compound in equivalent mole ratio from 1:1 to 1:5 in organic solvent; and   b) adding lewis acid catalyst into mixture obtained from a).   
     
     
         7 . The process for preparing the diethanolamine derivative chelating agent according to  claim 6 , wherein the organic solvent in step a) can be selected from 1,4-dioxane, 1,2-dichloroethane, dichloromethane, or mixture thereof. 
     
     
         8 . The process for preparing the diethanolamine derivative chelating agent according to  claim 7 , wherein the organic solvent in step a) is dichloromethane. 
     
     
         9 . The process for preparing the diethanolamine derivative chelating agent according to  claim 6 , wherein the cyclic anhydride compound in step a) is selected from maleic anhydride, succinic anhydride, glutaric anhydride, or phthalic anhydride. 
     
     
         10 . The process for preparing the diethanolamine derivative chelating agent according to  claim 9 , wherein the cyclic anhydride compound is selected from maleic anhydride, succinic anhydride, or phthalic anhydride. 
     
     
         11 . The process for preparing the diethanolamine derivative chelating agent according to  claim 6 , wherein the equivalent mole ratio between diethanolamine and cyclic anhydride compound is from 1:2 to 1:5. 
     
     
         12 . The process for preparing the diethanolamine derivative chelating agent according to  claim 6 , wherein the lewis acid catalyst in step b) is selected from boron trifluoride (BF 3 ) in organic solvent, zinc chloride (ZnCl 2 ), aluminium chloride (AlCl 3 ), tin chloride (SnCl 2 ), or mixture thereof. 
     
     
         13 . The process for preparing the diethanolamine derivative chelating agent according to  claim 12 , wherein the lewis acid catalyst is selected from boron trifluoride in organic solvent. 
     
     
         14 . The process for preparing the diethanolamine derivative chelating agent according to  claim 13 , wherein the lewis acid catalyst is selected from boron trifluoride in diethyl ether. 
     
     
         15 . The process for preparing the diethanolamine derivative chelating agent according to  claim 14 , wherein the lewis acid catalyst is boron trifluoride diethyl ethylate (BF 3 OEt 2 ). 
     
     
         16 . The process for preparing the diethanolamine derivative chelating agent according to  claim 6 , wherein the said process is operated at the temperature from ambient temperature to 80° C. 
     
     
         17 . The process for preparing the diethanolamine derivative chelating agent according to  claim 16 , wherein the said process is operated at the temperature from 40° C. to 60° C.